I have a theory about Pry and MC.
Although Pry says MC shut him out of the Storage Room of the Carcass, Pry is probably inside the time egg. Pry obviously knows how the time egg works and even chats with Nerus in the record. (Only Nerus and MC have conversations with Pry and only Nerus recognizes him being in a ‘story’ where Pry ‘should not exist’.) Pry doesn’t object when Nerus think he’s grudging, but he still offers fake records for Nerus to witness and says it’s heartbreaking when Nerus fails to recognise him. (Similarly, Pry acts like he hates MC and is likely to hurt MC, but I don’t think Pry would do that.)
After Obli met with the Demiurge (whose name is Samael), the Demiurge says Obli cannot be deceived anymore. Also, after reading the story of Aloys and Noch, Pry’s comments suggest that the story has changed (for example, Obli joining to witness their story). Pry does not seem surprised (also when Nerus responded to him in the prologue). Two possible explanations: one, this is a feature of a general time egg (or the specific one that MC is using); two, Pry is (producing and) expecting such emergence. I think the real function of the time egg is to hatch a soul, which may be possible because the egg says the Carcass stores the advanced soul technology. (The pattern on the egg looks like snake teeth.)
When MC is thinking about the couples, I am thinking about MC and Pry. When the shadow tells Alessia that Nerus has become something that he never intended to be, I guess if this would happen to Obli due to the aeon’s power (the light, the soul). Also, for the soul amnesia, Obli seems to forget something that Nomino knows and is important. I would take a wild guess that MC and Pry (also Nerus and Obli) are the reincarnation of a couple/pair or one thing being split into two halves.
When MC thinks about why he can’t find his records, he proposes that he just watched it but not recognised it. But I have a third argument that the room stores MC’s records but the thread is behind the current one. MC and we players use fleshy eyes to observe, but not Pry, voidborns, aeons, and the Carcass itself. Other possibilities include MC’s record in other storage room or MC’s record being deleted by Pry. (If I were MC, I would look for Pry’s record XD) But we don’t have enough info so I would leave it here.
All in all, the interaction between MC and Pry provides more clues. I hope MC will (be able to) explore the Carcass (and we can see the family cg soon).